Opto+ to coil+ and Opto- to coil- ? Unless 123tune are doing something weird to control the coil it should work if the system is using a standard 12v coil
It might be best to move the opto+ input to the tacho signal if you can and opto- to ground
the coil connection is designed for 12v points ignition so may not be liking the electronic distributor

No, the manual says opto+ grey/red wire to coil- and opto- to the coils +